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Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-.

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Drugs and Lactation Database (LactMed) [Internet].

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Aminosalicylic Acid

Last Revision: September 21, 2020.

Estimated reading time: 1 minute

CASRN: 65-49-6

image 134972628 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Limited information indicates that maternal aminosalicylic acid therapy produces low levels in milk and would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months. Exclusively breastfed infants should be monitored for rare instances of jaundice, gastrointestinal disturbances, hypokalemia, thrombocytopenia, hemolysis and hypokalemia if this drug is used during lactation.[1]

Drug Levels

Maternal Levels. One woman who was lactating, but not breastfeeding (time postpartum not stated) took a single 4 gram oral dose of aminosalicylic acid. A peak milk level of 1.1 mg/L occurred at 3 hours after the dose. The drug's half-life in milk was estimated to be 2.5 hours.[1] Using these data, a fully breastfed infant would receive a maximum of about 0.25% of the maternal weight-adjusted dosage.

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Aminosalicylic acid was used as part of multi-drug regimens to treat 2 pregnant women with multidrug-resistant tuberculosis throughout pregnancy and postpartum. Their two infants were breastfed (extent and duration not stated). At age 1.8 and 4.6 years, the children were developing normally, except for except for a mild speech delay in one at age 1.8 years, and failure to thrive in the other, possibly due to tuberculosis contracted after birth.[2]

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.


Holdiness MR. Antituberculosis drugs and breast-feeding. Arch Intern Med 1984;144:1888. Letter. PMID: 6548112. [PubMed: 6548112]
Drobac PC, del Castillo H, Sweetland A, et al. Treatment of multidrug-resistant tuberculosis during pregnancy: long-term follow-up of 6 children with intrauterine exposure to second-line agents. Clin Infect Dis. 2005;40:1689–92. [PubMed: 15889370]

Substance Identification

Substance Name

Aminosalicylic Acid

CAS Registry Number


Drug Class

Breast Feeding


Anti-infective Agents

Antitubercular Agents

Disclaimer: Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.


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